How many of you recall the movie Brazil? If you do, you'll also remember that it's all about the ducts.
AEC Product Manager, Stephen Roth, shared some of his insights on the MEP Analysis Extension for AutoCAD and Revit. The extension is available for download from the Autodesk Labs site:
One of the many responsibilities of HVAC engineers is to size air duct systems for buildings. Duct systems supply cooled and heated air from the central air conditioner and furnace to all of the rooms so as to ensure personal comfort. It is very important to properly size the dimensions of individual duct runs throughout the system so that:
- the proper amount of air flows into a room as to properly heat and cool without over or under heating/cooling, and
- the total pressure loss in the duct system does not exceed the pressure rating requirements of the fan that supplies the air.
Two utilities in the MEP Analysis Extension allow engineers to address both of these issues. The first utility is a “Duct Sizing Calculations” utility that performs duct sizing based upon air-flow, velocity, duct material type, and additional inputs. The results contain duct size dimensions (for rectangular, round, or oval shaped ducts), pressure loss values, and other pertinent information. One convenient feature is the “slider-calc” functionality that allows instantaneous results as the user ever-so-slightly increases or decreases different values using a slider control:
The second utility is the “Duct Fitting Pressure Loss Analysis” utility that allows engineers to determine the pressure loss in an individual duct fitting (such as an elbow or wye). Using these results, the engineer can determine the total pressure loss for a duct system. Some of the inputs that are required by this utility include the air flow, duct inlet and outlet dimensions, and air temperature. The final calculated result includes the total pressure loss through the duct fitting.
An engineer can use a combination of the above utilities to design simple duct systems in a building, ensuring that duct runs and air handlers are properly sized so that energy is not wasted on powering oversized fans.
So let us know what you think at [email protected]. Feedback on additional use cases that you would find valuable with the MEP Extension will help shape the future of this technology.